The invention relates to a bicycle frame for building an electric bicycle and an electric bicycle with such a frame. It also concerns a battery pack for such an electric bicycle and a home training arrangement. The invention also concerns a bicycle, an auxiliary motor for a bicycle, a control unit for such an auxiliary motor and a drive adapter.
Bicycles have long enjoyed great popularity as an economical, easy to handle and emission-free means of transportation. In recent decades, they have also found mass distribution as sports or fitness equipment, and particularly suitable types of bicycles emerged for various fields of sporting application. This includes mountain bikes (MTB) in various structural forms that were especially developed for use in terrain and especially mountainous terrain in addition to racing bicycles and bicycles optimised for recreational sports use on asphalt or light terrain (road bikes, city bikes or cross bikes).
On the other hand, the fundamentally already old idea of the electric bicycle has for years now been implemented again as an attractive product (“pedelecs”) and these bicycles have now experienced remarkable dispersion despite their heavy weight and high price. In particular, potential customers are older, less physically fit cyclists or cyclists who are not athletically ambitious. However, there are also sports-minded cyclists who are interested in electric bikes, whether for use on the way to work or because of the possibility of travelling further with them without overstressing their own physique and/or of increasing their travel speed.
There are very different attitudes towards pedelecs, especially among mountain bike riders, and there is hardly a market for these, in part due to the heavy weight design that hardly satisfies athletic ambitions, the poorer maneuverability and the reduced agility. Even considering visual aspects, the current pedelec designs cannot meet the expectations of ambitious athletic mountain bike riders.
DE 20 2004 014 189 discloses a bicycle with an auxiliary drive. Such auxiliary drives are usually mounted in the seat tube of a bicycle. They have a brushless DC motor and a transmission. Additionally, such auxiliary motors are connected with rechargeable batteries and control electronics. The rechargeable batteries provide such auxiliary motors with power. The rechargeable batteries of such systems are typically mounted on the outside of the bicycle, for example, in so-called saddlebags and are connected to the auxiliary motor via cables.
However, this arrangement also has a number of unwanted effects and drawbacks.
The cable connection is the first weak point of such systems. This is especially relevant for mountain bikes, which are often used in rough terrains and therefore can be subject to high impacts or external influences. For example, a saddle bag (in which the rechargeable batteries and the control electronics are mounted) can become loose from the saddle due to impacts to the bike, which in turn can interrupt the connection between the rechargeable battery, control electronics and auxiliary drive. Next, these components can be lost for similar reasons. The saddle bags, which are filled with rechargeable batteries, can also lead to injuries or damage to the bike if they fall. They can even be damaged by stone impact.
Furthermore, the attachment of additional structures, such as saddlebags for the inclusion of batteries, is undesirable for various other reasons. This can adversely affect the aerodynamics and the aesthetic appearance of the bike. For example, it may be undesirable, especially for athletic users, that others can see that they are using a bicycle with an auxiliary drive.
Furthermore, it should also be noted that the installation of such drive systems is often complicated. An inner bearing tube of a standard bearing must first be replaced with a special drive shaft. Furthermore, the drive must be mounted in the seat tube, which is only accessible after dismantling the saddle next to the seat post. A saddlebag for holding the rechargeable batteries must be installed and these rechargeable batteries must be connected to the drive in a conductive manner. Such assembly is time consuming and expensive and can in many cases only be performed by a trained specialist.